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Well I have a Renesis plate exhaust flange that matchs the engine ports exactly and 37mm is too small.
Take (port width x 2) + (port height + 2) and then divide that by Pi (3.142) and that will give you an equivalent pipe ID. It’s not 37mm I guarantee you
You do understand the dimensional difference between sch wall pipe and OD tube right?
I have an actual port !
I get the area of the port at 1075mm2 (46x24) - 28 for the radius
and the area of a pipe with an inside diameter of 37mm at 1075mm2 .
What do you get ?
Also : the port is actually on a bit of an angle so the actual area is a little less than 1075 .More like 1030mm2
I get the area of the port at 1075mm2 (46x24) - 28 for the radius
and the area of a pipe with an inside diameter of 37mm at 1075mm2 .
What do you get ?
I posted it in an edit on the other page, but I squared it without the radius and knew it’d lose some, here is what I have which seems larger than yours
15/16” wide x 2-1/8” tall (mine is taller than yours?) with 1/4” radius 1.69” dia = 42.9mm
So the radius corners took off more than I was approximating and I could use 1.75” OD x 16 Ga. for the siamese. Yeah I was off some there, but your main end ports are still quite a bit larger than than your pipe size. I just don’t agree with that.
I posted it in an edit on the other page, but I squared it without the radius and knew it’d lose some, here is what I have which seems larger than yours
15/16” wide x 2-1/8” tall (mine is taller than yours?) with 1/4” radius 1.69” dia = 42.9mm
So the radius corners took off more than I was approximating and I could use 1.75” OD x 16 Ga. for the siamese. Yeah I was off some there, but your main end ports are still quite a bit larger than than your pipe size. I just don’t agree with that.
The port is 46x24 ...... what you have there isn't a port .... What I have here is.
I had it on my engine and could have sworn it was flush, but I don’t have the best lighting there or eyes anymore either. But you still keep ignoring that the two end ports are a lot larger than 37mm if that is the actual size of the much smaller siamese center port.
Ok, looking at some past RX8 low mounts I have to believe that somewhere between the other sketch and this one that it’s going to fit in there. The V-band and IWG is a big benefit ...
I had it on my engine and could have sworn it was flush, but I don’t have the best lighting there or eyes anymore either. But you still keep ignoring that the two end ports are a lot larger than 37mm if that is the actual size of the much smaller siamese center port.
Well I admit that I've never heard that method of getting an equivalent pipe diameter you posted . What's the engineering behind that ?
But actual outer port area is 1030 (taking into account the port angle) and the pipe is 1075mm area so I would have thought that's fine.
I already addressed that back earlier in the thread. IMO you’re choking off exhaust flow from escaping the rotor chamber fully before the exhaust port closes at higher rpm such that PR in the rotor chamber is greater than PR at the turbo/wastegate. You keep assuming they’re equal, but I’m convinced they’re not and that’s part of the issue you’re having. I realize people do that on the 13B, but as you know the Renesis is different in many ways. So not only is it carrying over into the intake cycle the turbo is not receiving all of the energy to to power it more.
My philosophy is that the EFR 7163 will spool up fast even with the full port dia piping and then it will be powered by more flow and compound upon itself as rpms rise. Completely opposite approach.
If you want to do it your way use 2” pipes but then reduce it right at the turbo inlet only so you have velocity there with only minor resistance without the major restriction of the full pipe length being like that. That’s harder to do with a T4 flange though. You really need a v-band to do it that way, though maybe the T4 actuated butterfly flap on one side might make it work. I don’t really like those. Just one more thing to maintain/break/etc.
Just did a quick search on 'Equivalent diameter' which is the calculated diameter of a pipe that will give the same pressure loss as a rectangular tube . Using the online calculator for 44x24 (true size) I get an equivalent diameter of 35.1 .
Besides that , yes I do understand that there is some pressure drop across the pipes so internal pressure within engine is higher than at the turbine . How much that is , seems to be in contention here .
Have you considered alcohol injection for cooling to allow running a smaller intercooler?...
Originally Posted by Brettus
I tried W/M injection and I really didn't think it worked very well at all (on a Renesis) . I believe all the bends allow much of it come out of suspension and bead . Maybe if you could get closer to the ports it would work better . E85 (or any decent amount of ethanol) is a much better alternative ..... IMO
I was thinking straight methanol not water/meth. Granted as I mentioned, it does add complexity and likely corrosion concerns. And as Team alluded, you would likely have to work out some sort of fail safe in the event that the AI system fails. So maybe it's not worth the hassle to reduce IC size a little.
Looking forward to the results of this proposal if it comes to fruition.
You also have to consider the time factor; as RPM rises the time that the exhaust port is open grows smaller and smaller. At lower rpm I’m sure there’s enough time for it to clear sufficiently. At some point it has to start backing up, but again if you waited and then restricted at the turbo it’d see the velocity increase with only a minor restriction just at that point rather than restricting flow the entire length. Maybe you should go back and reread post #1 in your current turbo thread:
The 'Achilles heel' of the Renesis when turboed has always been the poor exhaust port flow.
Well, you compounded that with 37mm piping imo. When you were running the smaller 57mm turbine did you ever try 50mm manifold piping?
Which you seem to acknowledged the issue here, but blame the “ports” ...
May I ask what you measure for the main ports? I have trouble getting to my car due to my current situation. Based on the flange I get 2.06” ID, but those ports are also the same height as the siamese, which your port is measuring slightly shorter. I know you have them posted on the forum somewhere, but I haven’t found them searching yet. Thanks.
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Last edited by TeamRX8; 01-14-2018 at 12:46 PM.
Reason: Thanks
Also wanted to add that after talking to Elliot @ Turblown he recommended the TurboSmart actuator for the IWG, which should allow for the boost pressures I want to run, but also keep the IWG fully closed until it needs to open.
Don't want any exhaust flow getting past the turbine except when boost control is required. The 41mm IWG should be plenty sufficient for keeping that under control even with a 0.85 AR turbine housing and free-flowing manifold pipe sizing.
Well if I use 36mm width x your 46mm port height I get a 1.802" equivalent pipe ID. 2" OD x 16 Ga. tube has a 1.875" ID. Going to stay with that.
So the current plan for the turbo manifold is to use 2" OD tube fittings for the main pipes and then merge the center port in using 1.75" OD tube fittings that are all 16 Ga. T321 stainless steel material. This actually works well with an RB flange for emissions use by port-grinding the end ports out and butt-welding 2" OD tube to them, which is a perfect match, and then the 1.75" center port tube slides right in the provided 1.75" ID slip-in connection for the center port.
Sorry, I'm not upset with you, just frustrated with my personal situation. In that instance yes, but you are mixed up and just don't realize it. You have all the data, but came to the wrong conclusions in several instances imo. Yeah, you just said port without defining it when we were discussing the center port. That's why I should stop listening to everyone else and verify for myself. It's not against you or anyone else, it's just making sure I get it right for me.
I need to measure the area between the engine and frame rail for turbo fitment any way, just going to go do it now and get it over with.
on top of all that my laptop crashed and wasn't recoverable Wed nigh and I was upp all night rebuilding it to get half way functional again. Now W10 is doing all kinds of weird crap with my mouse pointer jumping between screens and stuff that I'm not intentionally trying to do and I can't figure out how to get it to stop. Driving me nuts ...
Well ... the reason I keep arguing the point about pipe size is that it seems central to your thinking about what you need to do on your setup . If we could actually come to a conclusion about it , it may well change your thoughts about how you design your system.
I really think your 'equivalent pipe size formula' is wrong . My search found a totally different formula which looks correct when you think about it logically. Because a round pipe is a more efficient shape than a rectangular one to flow air.
EDIT: I bluntly/rudely told Brettus to leave the thread. Can't believe I wasted my whole weekend arguing with that guy, but what's done is done. He can do his own thing in his thread and I'm going to do the same here. The results can speak for themselves regardless of what they are.
OK, well that BS aside I guess we're going to find out where the rubber hits the road. I was going to hold it back, but I don't care anymore. I already worked out a deal on an RX8 with someone on the forum and am just waiting for him to remove some aftermarket parts that I didn't want before we close on it. I'm also in discussion with the builder about the engine and am working with a several vendors on some preliminary parts purchases. Not sure when it will all come together, but Summer this year is probably a reasonable estimate.
I'm glad I went down to take a few measurements on the car. I recognized another advantage of the 4-port engine choice; not having the APV assembly opens up a bunch of vertical space between the exhaust manifold and the chassis/LIM for fitting the turbo assembly. That's a significant limitation that I won't have to be handcuffed by. Coupled with a custom engine mount bracket I'm not expecting any fitment issues with the EFR 7163 turbo and already have this piped in my head and will draw up some sketches soon. Feeling pretty excited now and am fully confident with my choices for turbo, manifold piping, etc. I'll get into that more when I post the sketches later. It will provide a reasonably short and well directed flow into the turbine inlet, another issue I have with how many other low-mount manifolds are piped.
Siamese port will be 1096.27 - ((24-18) x 46) = 820.27mm˛
Guess we can ignore the .27
Inner diameter:
2" gives 25,4˛ x 3.14 = 2026mm˛
1,5" gives 19,05˛ x 3.14 = 1140mm˛
I do not know the inner diameter that Team is planning to use(Team?), but my point in previous pulse energy post, is that if it's possible to fabricate, it would be beneficial to square the pipe so that its matching the shape of port in one end, and turbo inlet in other end, with a gradual transition. If so, there will be a difference in calculation, because we need to look at the outer path. Main port inner envelope is (2x18)+(2x40)+(3,14x6) = 135mm.
2" gives 50.8 x 3.14 = 160mm
1,5" gives 19,05˛ x 3.14 = 120mm
Now we are in between, and if Teams 2" pipe has thick walls, this might match better.
Anyone got a inconel 3D printer in the garage? Or someone got mad skills with a hammer
EDIT: I can see that Team gave 1.875 as inner diameter for his choice of 2". This gives an inner envelope of (1.875*25,4mm) x 3,14 = 150mm.
It doesn't matter. The Racing Beat flange I'm going to use matches perfectly with my plan to use 2" OD x 16 Ga Tube fittings (1.875" ID) on the two end ports and 1.75" OD x 16 Ga. tube fittings (1.625" ID) on the center port as well. The flange also provides the air injection function needed to pass OBD2 emissions testing. The cast flange already has smooth transitions from rectangular to round, except they're all for 1.75" OD tubing. I just have to port grind the two end ports out smoothly from 1.75" ID size to the 2" ID size; shouldn't be too difficult. I'll post it up eventually . I have the manifold piping layout all figured out now as well and will eventually post up a basic hand sketch for it too.
I have other reasons for doing it this way, but am not going to explain why; the results can speak for themselves whichever way it turns out. Otherwise I feel like all the pieces are falling into place ...
01-14-2018, 02:26 AM
Or someone got mad skills with a hammer 